A clinical phenomenology of the concept ‘unconscious fantasy’ attempts to describe it from a ‘bottom-up’ perspective, that is, from the immediate experience of the analyst working in session. Articles of psychoanalytic authors from different persuasions are reviewed, which taken as a whole would shed some light on how the concept of unconscious fantasy takes shape in the analyst's mind during the session with the patient. A clinical phenomenology in three steps is described. Each step is illustrated by clinical material. Current controversies around the concept of unconscious fantasy (or phantasy) are still trapped in the discussion if and how they are really unconscious. The strategy to describe from a ‘bottom-up’ perspective the process of how the analyst's mind embraces the idea that an emerging phenomenon in the relationship with the patient can be defined as ‘unconscious fantasy’, allows us to elude the question as to whether or not we believe that unconscious fantasies exist at all, since we are neither required to assert or deny such a prior existence in order to describe the process of elaboration which, in the end, does formulate a fantasy as fantasy.